1. Field of the Invention
The present invention relates generally to abrading. More specifically, the invention is an automatically adjustable abrading sharpener apparatus having an adjustable pitch and a pneumatic valve operated reciprocator for sharpening helical-cut rotary mower blades with a conventional fixed grinding wheel.
2. Description of the Related Art
The relevant art of interest describes various metal implement sharpening machines, but none discloses the present invention. There is a need for an economical, ergonomic, automated pneumatic valve operated mower blade sharpener apparatus adaptable to most fixed grinding wheel apparatus for eliminating the generation of excessive heating of the blade, the requirement for holding the blade manually, and reducing sparks, dust, noise, and danger to the user during the grinding procedure. The related art of interest will be described in the order of perceived relevance to the present invention.
U.S. Pat. No. 1,945,044 issued on Jan. 30, 1934, to Albert M. Johnson et al. and its referenced U.S. Pat. No. 1,783,019 issued on Nov. 25, 1930, to Albert M. Johnson describe reciprocating hydraulically operated honing machines for honing cylindrical metal surfaces such as engine cylinders, bearing bushings and the like. The control mechanism is shown by the earlier patent, and actuated by the main reciprocal member, usually the tool carriage, to act on a valve element or clutch element, depending on whether the machine is driven by hydraulic or mechanical power to control the drive for the reciprocating member. Two vertical housings contain spindle driving shafts and reciprocatory head structures. The honing tools comprise a series of longitudinally positioned and spaced honing stones arranged in retaining heads. The apparatus is distinguishable for requiring two reciprocating driving shafts and limited to honing only cylindrical metal surfaces.
U.S. Pat. No. 2,738,624 issued on Mar. 20, 1956, to William T. Osborn describes a reciprocating sickle mower blade sharpener apparatus using belt action as the reciprocator. The apparatus comprises a blade support and a grinding wheel having a diamond shaped cross-section which is rotatable about its axis in sharpening engagement of the teeth of a blade sequentially, and is bodily movable relative to the teeth to contact the entire cutting teeth surfaces. The blade support is mounted to cooperate with the grinding teeth by moving the blade held thereby slightly relative to the grinding wheel to compensate for the bodily movement of the grinding wheel. The rotation and reciprocation of the grinding wheel is powered by a prime mover through belt transmission means. The apparatus is distinguishable for requiring a bodily movable grinding wheel and limited to contacting the entire cutting teeth having triangular surfaces.
U.S. Pat. No. 5,618,226 issued on Apr. 8, 1997, to Hisashi Ueyama describes an angle-adjustable reciprocating grass cutting blade sharpener. A circular shaped grindstone is held by a fixed upright support which has an arcuate guide slot for tilting the grindstone. The blade mount has a horizontal platform with an arcuate edge which is a downwardly inclined surface for placing the trimmer blade. The blade is moved by hand to sharpen each tooth separately. The apparatus is distinguishable for requiring hand-sharpening, a specifically shaped blade mount and a grindstone on a separate mount which can tilt the grindstone.
U.S. Pat. No. 4,495,734 issued on Jan. 29, 1985, to Hans Rauch describes a grinding arrangement of a chopping cutter incorporated in a drum-chopper machine comprising a vertical cylindrical grinding stone which reciprocates its motion via a piston rod and a working cylinder operated by a control valve. The apparatus is distinguishable for being limited to sharpening only blades of a drum-chopper machine.
U.S. Pat. No. 4,718,198 issued on Jan. 12, 1988, to Werner Komossa et al. describes an apparatus for grinding the cutting edges of multiple knives in a rotary tobacco cutting machine comprising rectangular knives positioned across the width of a rotating drum sharpened by a circular grinding wheel rotated and moved across the width of the rotating drum by a motor on a frame with a V-belt transmission. The grinding wheel can be as wide as the rotary cutting machine. The apparatus is distinguishable for requiring a rotary tobacco cutting machine with rectangular knives and a movable or stationary cylindrical grinding wheel.
U.S. Pat. No. 5,159,784 issued on Nov. 3, 1992, to James E. Varner, Sr. et al. describes a portable apparatus for sharpening knives comprising a grinder with a conical face held in a guide bracket of a cylindrical portable blade sharpener body (motor). The grinding angle is varied for different blades by different grinders having differently angled conical surfaces. The portable tool is distinguishable for adjusting the angle of the sharpened blade tip by requiring differently angled grinding stones.
Japan Patent Application No. 54-65898 A published on May 26, 1979, for Tatsumi Matsumoto describes a stop finger apparatus comprising, as best understood, a semiconductor chip polisher machine having automatic detecting means of the chip position by a finger means, and eliminating any manual regulation in applying the grinder to the chip. The apparatus is distinguishable for being limited to a semiconductor chip polishing machine.
Japan Patent Application No. 57-127654 A published on Aug. 7, 1982, for Eikichi Tanaka describes an automatic 1S grinder for the specific shape of a sickle stock blade comprising a movable grinding belt driven by a motor and controlled by a hydraulic cylinder having an arm to adjust the position of a sickle blade via two oscillating plates on individual pivot pins. The apparatus is distinguishable for being limited to sharpening arcuate sickle blades and requiring a movable grinding belt for different graded areas of a sickle blade.
Germany Patent Application No. DE 38 41 829 A1 published on Jul. 6, 1989, for Zbynek Albrecht et al. describes a grinding device for harvest choppers with a rotationally driven drum having a series of knives on its surface. A hollow cylindrical grinding roll positioned above the drum has a shaft adjustable in two coaxial eccentrics by hydraulic or pneumatic cylinders. The apparatus is distinguishable for requiring a rotating drum with knives for sharpening.
Germany Patent Application No. DE 41 28 483 A1 published on Mar. 4, 1993, for Hans Rauch describes a grinding slide which transverses to-and-fro along a slideway parallel to the rotational axis of the cutting cylinder. This apparatus is analogous to the apparatus discussed in U.S. Pat. No. 4,495,734 above and distinguishable for the same reasons.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a mower blade sharpener solving the aforementioned problems is desired.
The apparatus is an automatic reciprocating holder means to sharpen lawn mower blades conveniently with any stationary circular flat-edge faced grindstone with its drive motor affixed to a common base. A housing having open opposing sides contains a blade holder with securing means. The housing is automatically moved back and forth a limited distance on parallel rails to sharpen the lawn mower blade. The housing is driven by a hydraulic system designed with a reciprocating movement of approximately 4 inches in a cycle duration of approximately a second.
Accordingly, it is a principal object of the invention to provide an automatic lawn mower blade sharpening apparatus.
It is another object of the invention to provide an automatic lawn mower blade sharpening apparatus providing a reciprocating motion to the lawn mower blade affixed in a housing.
It is a further object of the invention to provide an automatic lawn mower blade sharpening apparatus utilizing a conventional flat side surfaced and fixed grindstone device.
Still another object of the invention is to provide an automatic lawn mower blade sharpening apparatus reciprocating by pneumatic means.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.